Accurate characterization of the mechanical response of collagenous tissues is critical for investigations into mechanisms of soft tissue injury. These tissues are inherently viscoelastic, exhibiting strain-rate dependent stiffnesses, creep, and stress-relaxation. The strain-rate features of the failure portion of the stress-strain curve are less well developed. Collagen-distribution based models are improving and capable of reproducing the non-linear aspects of the elastic response of soft tissues, but still require parameterization of failure regions. Therefore, the purpose of this investigation, was to determine whether the parameters characterizing the rate of damage accumulation in a collagen-distribution model are proportional to strain rate.

Fifty rat tail tendons were subjected to one of five different strain rates (0.01, 0.05, 0.1, 0.15, 0.20 s⁻¹) until failure in an uni-axial strain test. To test the hypothesis that the parameters associated with damage rate are proportional to strain rate, a collagen distribution model was employed with the parameters describing the rate of fibre damage being obtained by least-squares and regressed against the strain rate.

The breaking function was found to be proportional to strain rate, with a proportionality constant of 60.7 s⁻¹. Properties characterizing the failure portion of the stress-strain curves for rat tail tendons are also reported. The Young's Modulus did not vary with strain rate and was found to be 103.3 ± 49.5 MPa. Similarly, failure stresses and strains did not vary across the strain rates tested, and were 15.6 ± 6.1 MPa and 32.2 ± 9.1%, respectively.

胶原组织机械反应的准确表征对于研究软组织损伤的机制至关重要。这些组织固有地是粘弹性的，表现出取决于应变率的刚度，蠕变和应力松弛。应力-应变曲线的破坏部分的应变率特征欠佳。基于胶原蛋白分布的模型正在改进，并且能够再现软组织弹性响应的非线性方面，但仍需要对失效区域进行参数化。因此，本研究的目的是确定表征胶原分布模型中损伤累积率的参数是否与应变率成正比。

对五十只大鼠尾部肌腱进行五种不同的应变率之一（0.01、0.05、0.1、0.15、0.20 s ^-1），直到单轴应变测试失败。为了检验与损伤率相关的参数与应变率成正比的假设，采用胶原蛋白分布模型，该参数描述了通过最小二乘获得的纤维损伤率并相对于应变率进行回归的参数。

发现断裂函数与应变率成比例，比例常数为60.7 s ^-1。还报道了表征大鼠尾腱的应力-应变曲线的破坏部分的特性。杨氏模量没有随应变速率变化，发现为103.3±49.5MPa。同样，破坏应力和应变在测试的应变速率中也没有变化，分别为15.6±6.1 MPa和32.2±9.1％。